a. until Microsoft corrects the version of usbser.sys in Windows 10, repeat steps 2a-2c after each major Windows 10 update

a. until Microsoft corrects the version of usbser.sys in Windows 10, repeat steps 2a through 2c after each major Windows 10 update

Error 8020: Error reading comm device

As described by Microsoft, this error message is the result of a defective serial port device driver. It should be resolved by by obtaining an updated device driver from your serial port or USB adapter manufacturer.

Windows 10

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Some USB devices that emulate serial ports employ the usbser.sys driver. Unfortunately, the version of usbser.sys included with Windows 10 is defective; as a result, DXLab applications running on Windows 10 report an 8020 error when they attempt to communicate with such USB devices. There are two ways to correct this:

replace the usbser.sys file in Windows/System32/Drivers with the older version downloaded in the previous step; this may require changing security permissions by right-clicking the entry for usbser.sys in Windows Explorer, selecting Properties, and then selecting Security